This invention relates to a differentiation-inducing agent. In particular, this invention relates to the use of a novel benzamide derivative or anilide derivative for an anticancer drug or other drugs based on its differentiation-inducing activity.
Cancers have now become a top cause of death, exceeding heart and cerebrovascular diseases, and so many studies have been conducted with enormous expense and time to overcome cancers. They have not been, however, overcome in spite of a variety of investigations for therapy such as a surgical operation, a radiation therapy and thermotherapy. Among those therapies, chemotherapy is one of the main area for cancer treatment. To date, however, no satisfactory drugs have been discovered, and thus an anticancer drug with reduced toxicity and high therapeutic effect has been desired. Many of the conventional anticancer drugs show their effect by affecting mainly DNA to express their cytotoxicity and then injuring carcinoma cells. However, since they do not have sufficient selectivity between carcinoma cells and normal cells, adverse reactions expressed in normal cells have limited their use in therapy.
Meanwhile, differentiation-inducing agents among anticancer drugs are intended to induce differentiation of carcinoma cells for controlling their infinite proliferation, rather than directly kill the cells.
The agents may, therefore, be inferior to the anticancer drugs directly killing carcinoma cells, with regard to involution of a carcinoma, but may be expected to have reduced toxicity and different selectivity. In fact, it is well known that retinoic acid, a differentiation-inducing agent, may be used for treatment of acute promyelogenous leukemia to exhibit a higher effect [Huang et al., Blood, 72, 567-572(1988); Castaign et al., Blood, 76, 1704-1709 (1990); Warrell et al., New Engl. J. Med. 324, 1385-1393(1991) etc.]. In addition, vitamin D derivatives exhibit differentiation-inducing effect, and thus their application for anticancer drugs have been investigated [e.g., Olsson et al, Cancer Res. 43, 5862-5867(1983) etc.].
As the results of these investigations, there have been reported applications for anticancer drugs, of a variety of differentiation-inducing agents such as vitamin D derivatives (JP-A 6-179622), isoprene derivatives (JP-A 6-192073), tocopherol (JP-A 6-256181), quinone derivatives (JP-A 6-305955), noncyclic polyisoprenoids (JP-A 6-316520), benzoic acid derivatives (JP-A 7-206765) and glycolipids (JP-A 7-258100). There have been no agents having sufficient level of effect for cancer treatment in spite of the investigations, and thus there has been greatly desired a highly safe agent effective to a variety of cancers.
An objective of this invention is to provide a compound which exhibits differentiation-inducing effect and is useful as a pharmaceutical agent such as therapeutic or improving agents for malignant tumors, autoimmune diseases, dermatologic diseases and parasitism.
We have intensely attempted to achieve the above objective and have found that a novel benzamide derivative and a novel anilide derivative having differentiation-inducing effect show antitumor effect, leading to this invention. Specifically, this invention provides a compound represented by formula (1) or a pharmaceutically acceptable salt thereof, 
wherein A is an optionally substituted a phenyl or heterocyclic group which has 1 to 4 substituents selected from the group consisting of a halogen atom, a hydroxyl group, an amino group, a nitro group, a cyano group, an alkyl group having 1 to 4 carbons, an alkoxy group having 1 to 4 carbons, an aminoalkyl group having 1 to 4 carbons, an alkylamino group having 1 to 4 carbons, an acyl group having 1 to 4 carbons, an acylamino group having 1 to 4 carbons, an alkylthio group having 1 to 4 carbons, a perfluoroalkyl group having 1 to 4 carbons, a perfluoroalkyloxy group having 1 to 4 carbons, a carboxyl group, an alkoxycarbonyl group having 1 to 4 carbons, a phenyl group and a heterocyclic group;
X is a bond or a moiety having a structure selected from those illustrated in formula (2) 
wherein e is an integer of 1 to 4; g and m are independently an integer of 0 to 4; R4 is hydrogen or an optionally substituted alkyl group having 1 to 4 carbons, or the acyl group represented by formula (3) 
wherein R6 is an optionally substituted alkyl group having 1 to 4 carbons, a perfluoroalkyl group having 1 to 4 carbons, a phenyl group or a heterocyclic group; R5 is hydrogen or an optionally substituted alkyl group having 1 to 4 carbons;
n is an integer of 0 to 4, provided that when X is a bond, n is not zero;
Q is a moiety having a structure selected from those illustrated in formula (4) 
wherein R7 and R8 are independently hydrogen or an optionally substituted alkyl having 1 to 4 carbons;
R1 and R2 are independently a hydrogen atom, a halogen atom, a hydroxyl group, amino group, an alkyl group having 1 to 4 carbons, an alkoxy group having 1 to 4 carbons, an aminoalkyl group having 1 to 4 carbons, an alkylamino group having 1 to 4 carbons, an acyl group having 1 to 4 carbons, an acylamino group having 1 to 4 carbons, an alkylthio group having 1 to 4 carbons, a perfluoroalkyl group having 1 to 4 carbons, a perfluoroalkyloxy group having 1 to 4 carbons, a carboxyl group or an alkoxycarbonyl group having 1 to 4 carbons;
R3 is a hydroxyl or amino group.
This invention also provides an anilide having the structure represented by formula (13) 
wherein A and R3 are as defined above; B is an optionally substituted a phenyl or heterocycle group; Y is a moiety having xe2x80x94COxe2x80x94, xe2x80x94CSxe2x80x94, xe2x80x94SOxe2x80x94 or xe2x80x94SO2xe2x80x94 which is linear, cyclic or their combination and links A and B; and in which the distances between the centroid of ring B (W1), the centroid of ring A (W2) and an oxygen or sulfur atom as a hydrogen bond acceptor in the moiety Y (W3) can be as follows; W1-W2=6.0 to 11.0 xc3x85, W1-W3=3.0 to 8.0 xc3x85, and W2-W3=3.0 to 8.0 xc3x85; preferably W1-W2=7.0 to 9.5 xc3x85; W1-W3 is 3.0 to 5.0 xc3x85; and W2-W3 is 5.0-8.0 xc3x85; or a pharmaceutically acceptable salt thereof.
The novel benzamide derivative and the novel anilide derivative of this invention have differentiation-inducing effect and are useful as a drug such as a therapeutic or improving agent for malignant tumors, autoimmune diseases, dermatologic diseases and parasitism. In particular, they are highly effective as a carcinostatic agent, specifically to a hematologic malignancy and a solid carcinoma.